1. Field of the Invention
This invention relates to a medical apparatus for the removal of deposits, such as plaque, from the walls of arteries and/or veins, which is vessel-insertable, practical, withdrawable and directable, and which eliminates such deposits by slicing off portions with cutting edges.
2. Description of the Prior Art
Arteriosclerosis, a chronic, progressive, degenerative disease, particularly when located on the inner surface of artery walls, is an illness occurring frequently in the civilized world, most commonly during the second half of normal life spans. For example, about 90% of such cases are the cause of arterial blockage diseases, one of the most frequent causes of death. As a result of penetration of thrombocytes in the cell interspaces, followed by lipoid-containing deposits, the inner-most portion of walls of the vessels develops what is known as atheromas changes, which leads to the death of cells and, finally, expands the connecting tissue at this artery wall site (sclerosis). As a result of these changes, the artery wall loses its normal elasticity. Focal deposits, especially Cholesterin crystals that also penetrate to the middle of the vessel wall, lead to inflammatory reactions and more cell deaths. This results in calcium deposits, which cause growths in the vessel lumen and later produce thrombosis.
In some cases, arteriosclerosis can be treated with medicines, dilating the vessel to increase the flow of blood. In some cases, physio-therapeutic methods have been shown to improve circulation. In still other instances, surgical procedures have been developed to treat arteriosclerosis. The surgical treatment of arteriosclerosis changes when particular organs or parts of the body are involved. Vascular surgery can be successfully applied, particularly in the following cases:
a) Arteriosclerosis alteration to the carotid artery which supplies blood to the brain; PA1 b) Arteriosclerosis alteration to the coronary arteries, that is, coronary bypass and implanting; PA1 c) Serious arteriosclerosis which affects the supply of blood to the extremities; PA1 d) Arteriosclerosis to the kidney arteries; and PA1 e) The removal of aneurisms. PA1 a) Bypass surgery during which the plugged artery is replaced by a section of the patient's vein or artery or synthetic material in the form of a vessel, to bridge the flow of blood into certain areas; PA1 b) Endarterectomy; PA1 c) Implanting of a patch after endarterectomy; PA1 d) Implanting of a vessel prosthesis, either as a replacement or bypass for the arteriosclerosis artery; PA1 e) Sympathectomy; PA1 f) Removing arteriosclerosis changes using a balloon catheter.
With arteriosclerosis change, the following surgical techniques are generally applied:
It is known that arteriosclerosis changes are located mainly on internal walls of arteries, while the external walls remain relatively normal. When intersclerotic material is removed or sliced from the internal wall, the surface is left smooth. U.S. Pat. No. 4,765,332 teaches an atherectomy apparatus for surgical excision of atheromas, such as plaque deposits in an artery. The apparatus, after insertion into the desired vessel, operates by first penetrating the plaque in a forward direction with a conically-pointed metal tip and then pulling the tip back in a retrograde direction, which tip includes a cylindrical cutting edge, to shave off a cylindrical layer of the plaque. To enlarge the lumen of the plaque, sequentially larger diameter tips are progressively used. In addition to the necessity of changing tips to progressively enlarge the lumen of the plaque, an obvious disadvantage, this device has the further disadvantage that the sharp edges of the cutting portion of the tip are directed from the inside to the outside of the vessel, which could lead to the injury of healthy vessels. Similar devices are also taught by German reference 1,909,080, which discloses a probe having a protecting cap with a cutting edge connected to a tube which runs through a body which is movable toward the protecting cap such that material which is sliced from the arterial wall is retained within the protecting cap; British patent application GB 2,044,103 which teaches a cutting device for removing material from stenoses within blood vessels having a head mounted in tandem with a body, both the head and body having cutting edges such that, when inserted into a blood vessel, the head and body are positioned on opposite sides of the stenoses to be removed, the head being drawn toward the body causing the cutting edges on the head and the body to cut through the stenoses; U.S. Pat. No. 5,074,871, which teaches a catheter atherotome, for performing partial atherectomy in an artery having an expansible cutter head; U.S. Pat. No. 4,957,482 and related U.S. Pat. No. 4,842,579, which teach a flexible rotary catheter for cutting, ingesting and removing an obstruction from an artery; and U.S. Pat. No. 4,747,821, which discloses a flexible, small diameter catheter having a working head with a non-sharp impacting surface which is rotated at a high rate of speed by an associated drive means within the catheter.
Other devices for effecting openings in arteries clogged with plaque are taught by European Patent Application 0,117,519 which discloses a catheter having electrical terminals and a probe with a screw-type element disposed therein for expanding the circumference of the probe for pushing through the clogged artery; French reference 1,585,065, which discloses a surgical instrument for breaking through plaque and arteries; German reference DE 3,800,777 A1, which discloses a thermal, sound apparatus with laser means for angioplasty drawing pins; and German reference DE 3,320,984 A1, which discloses a catheter having an end portion, the circumference of which is expandable, for pushing through a blockage.
See also U.S. Pat. No. 5,047,041, which teaches a surgical device for cutting and removing venous valves, having a valve cutter with a fixed, non-expandable, circular cutting head affixed to a cable or wire, the cutting edge of which slices through the material to be removed as the device is pulled through a vein; U.S. Pat. No. 4,952,215, which teaches a valve valvulotome for preparing veins in situ for arterial bypass; U.S. Pat. No. 5,026,383, which teaches an apparatus for in situ cutting through one-way valves in a vein having a cutting catheter and a pulling catheter, the pulling catheter being advanced through the vein in a normal direction of blood flow and then connected to a cutting catheter and pulled back reversely through the one-way valves, the valve cusps of which are severed by cutting blades on the cutting catheter; U.S. Pat. No. 5,061,240, which teaches a balloon-tip catheter for tearing away one-way valves in a vein having an arrowhead shape when inflated, with an annular groove formed in the arrowhead base adjacent to and extending around the catheter tube; U.S. Pat. No. 5,049,154, which teaches an adjustable intraluminal valvulotome; U.S. Pat. No. 4,794,928, which teaches an angioplasty device having an operative member for removing and/or crushing an obstruction in a vessel such as a balloon, cutting rotors, fiber meshes and lasers; U.S. Pat. No. 4,685,458, which teaches a catheter having an element such as a fiber optic emitting laser energy, a heated element or a knife for intersecting and releasing undesired material in a blood vessel; U.S. Pat. No. 4,493,321, which teaches a venous valve cutter having a blade drawn by a rod attached centrally so that a portion of the blade extends on either side of the rod; U.S. Pat. No. 4,273,128, which teaches a coronary cutting and dilating instrument having a flexible probe at a distal end for guidance through a coronary artery followed, in succession, by one or more radially-extending knife blades for making a coronary incision and an inflatable balloon for dilating the stenotic artery zone immediately after the incision; U.S. Pat. No. 3,764,427, which teaches a vein-stripping instrument having a cable formed from a mono-filament of axially-oriented synthetic thermoplastic material, with a tubular plastic cap ultrasonically welded to each end; U.S. Pat. No. 3,508,553, which teaches a surgical vein-stripping instrument, having a cable with rounded end portions to which are attached bullet-shaped tips; U.S. Pat. No. 3,230,949, which teaches a gastroesophageal catheter having a flexible tube with a head attached to one end, the head comprising a plurality of cutting apertures communicating with the interior of the tube; U.S. Pat. No. 2,868,206, which teaches a vein stripper having an elongated slender wire and a bucket member slidable thereon; and International Patent Application PCT/US89/00634, which teaches a valvulectome, having an elongated probe with a tip and an actuating rod which moves a pair of blade members between retracted and expanded positions.